That a private enterprise wouldn’t be able to make this work should give us a hint that it doesn’t benefit enough people for it to be worthwhile, opera is a luxury good consumed by relatively few, relatively affluent people. Why should the taxpayer subsidize their hobby? Actors don’t need a billion dollar opera house to perform, they could do it in a school auditorium if necessary. Those tax dollars could have been spent on any number of other things like healthcare and education.
Making it cheaper doesn’t change people’s taste, it’s still mostly for the rich, now they’re just getting a subsidy they didn’t need from the taxpayer. If people want to spend their money on art that’s perfectly fine, what I’m objecting to is the taxpayer being obligated to do so.